This module is a variation on the 1973 Classic Serge Negative Slew module. It is a forerunner to the popular Dual Universal Slope Generator. It is presented here for those who want to build themselves a classic Serge. There are two Negative Slew modules on the PCB. It can be used as both a falling slew rate controller, or a downwards sloping ramp LFO by hooking the pulse out into the input.